The Mi 4 mobile version shows no service after installing the card

1. It may be that there is no service due to the problem of the mobile phone card (such as arrears and invalid cards), you can reinsert a new mobile phone card into the mobile phone to try.

2. It may also be that there is no signal near the mobile phone, resulting in no service on display, you can test it in a different place with a signal.

3. It may also be a system problem that causes no service to be displayed after installing the card, you can restart the phone to try, if necessary, you can consider restoring the system of the mobile phone to the factory setting state or upgrading to the latest version to solve the problem.

4. Or there is a problem with the hardware of the mobile phone that causes the display to have no service, such as the failure of the baseband, RF antenna, internal circuit, etc. of the mobile phone; It is necessary to contact Xiaomi's after-sales service to test and repair the mobile phone to solve the problem.

Hello. 1. If it is not the reason for the poor signal of the environment you are in, please open the settings Mobile Network Network Type Selection Choose to use only 2G network and try to see if it is normal.

2, if it doesn't work, remove the SIM card, reinstall it again, try to see if it's normal, 3, still doesn't work, it is recommended that you change the SIM card to try it.

4. If it still doesn't work, please take your mobile phone to a Xiaomi authorized repair point near you or Xiaomi Home for testing.

Mi Home address and ** query.

Mi Home is open from Tuesday to Sunday, from 10 a.m. to 6 p.m.

**The after-sales principle of Xiaomi mobile phones and Redmi mobile phones and Xiaomi tablets is the failure of non-human damage: return within seven days, replacement within fifteen days, and within the one-year warranty period, non-human damage is completely free.

The phone does not recognize the SIM card and shows no service processing method:

1. Please confirm whether the SIM card type is correct according to the mobile phone model. An incorrect SIM card can damage the card tray and card slot or even fail to be removed;

2. Please make sure to use a standard SIM card. Do not use a non-standard SIM card or cut the card by yourself, cutting the card can easily cause the SIM card to be unable to recognize or damage the mobile phone, it is recommended to go to the business hall to change the original standard SIM card;

3. Please confirm whether the card is placed correctly. Whether the notch of the SIM card corresponds to the card slot;

4. Please confirm whether the surface of the SIM card is dirty. If the SIM card has been used for a long time, you can wipe the surface of the chip with alcohol, or go to the business office to replace the original standard SIM card. If the SIM card is used for a long time, the metal surface is easy to be oxidized, which is easy to cause probabilistic card recognition;

5. Do not plug or unplug the SIM card when the device is turned on. After inserting the SIM card, please restart your phone and try;

6. If the problem still exists, please back up the data in advance and bring the purchase invoice to the after-sales service point for maintenance.

Xiaomi mobile phones have no service, and the reasons why they can't play are: <>

Reason 1) SIM card problem. Here's how to fix it:

1. Take out the SIM card, erase it with an eraser, put it back and try again.

2. Change your SIM card with someone else's, and see if your mobile phone and other people's mobile phones have a signal after you change it, if you still don't, it's a problem with your mobile phone.

Reason 2) Mobile phone hardware problems. Here's how to fix it:

1. The operator who called the ** card asked the customer service to refresh the background of the SIM card. 2. If none of the above can be solved, it is recommended to take it to a mobile phone repair station to check it.

Reason 3) Entering a non-service area or a place where there is no signal.

If you want to repair it yourself, it is recommended to try it according to the following methods:

2. Wipe the contact point between the mobile phone card and the mobile phone (whether the SIM card is in poor contact) or replace a SIM card with a test (whether the SIM card is aged or damaged).

3. Back up your phone's data (**book, SMS information, multi** data, etc.) and restore your phone's factory settings.

If the problem persists, there may be a problem with the system or hardware, and the nearest after-sales service center is selected for further testing.

If your phone can't read the card or the SIM card can't be detected, there may be one of the following situations:

1. The contact between the metal contacts of the mobile phone card and the mobile phone is insufficient.

Second, the mobile phone card is damaged.

3. Whether the location is a signal blind area or suddenly no signal.

Fourth, you can try to put the card on other mobile phones to try, and judge whether it is a problem with the card or the mobile phone through the method of changing the card and changing the phone.

Hello. What kind of card are you using, whether it is a mobile card or a Unicom card or a telecom card, and it is a card of several gigabytes.

The card is not inserted properly, or it is not activated.

It may be a problem with the signal, it may be a problem with the SIM card.

Hello. It is recommended that you check the collapse code according to the following method:

Whether the SIM card is inserted correctly.

Whether the wrong SIM card is inserted, such as the standard version inserts the telecom SIM card, etc.

Go to Hardware Detection to see if the SIM card is working properly (enter * * on the dial screen). If the SIM status is normal, go to step 5, or if the status is unknown, go to step 4.

Try to replace a different SIM card, if the status is still unknown during hardware testing, it is recommended to go to the repair point for testing; If the detection status is normal, it is recommended to go to the carrier to replace a SIM card (the SIM card may be aging).

Whether the network type is correct and whether the carrier selects Automatic. (China Unicom selects 3G priority, mobile selects only 2G, and China Telecom selects automatic).

If the network type of the non-telecom mobile phone is CDMA automatic, you need to change the network type to "WCDMA Preferred" in the mobile phone information (**) to solve the problem.

Whether there is no source forest in the area. You need to check whether other mobile phones on the same network have signals.

Back up your data, flash to the latest system version and try again.

If the above methods still do not help you solve the problem, please go to your nearest repair point for repair inspection.